Physicians should be cautious in prescribing broad-spectrum antibiotics, particularly vancomycin and the fluoroquinolones, because widespread use of these drugs is promoting antibiotic resistance. Resistance is now found in many organisms, including staphylococci, enterococci, streptococci, pneumococci, and Pseudomonas aeruginosa. Some resistant strains can be treated with alternative narrower-spectrum antibiotics. In addition, five newly licensed antibiotics are available, but they should be used judiciously because of their side effects, high cost, and ability to promote additional resistance.